Accelerated Corrosion of Aluminum Alloy and Determination Method of Equivalent Accelerated Relationship
A double-bridge connection method is proposed for rapid determination of the equivalent accelerated relationship between laboratory accelerated corrosion environment spectrum and actual atmospheric exposure for aviation aluminum alloys. The method employs corrosion electricity and corrosion weight loss as equivalent parameters, enabling calculation of the equivalent acceleration relationship without long-term outdoor exposure test pieces, using atmospheric environment monitoring data, laboratory corrosion weight loss tests, and short-term atmospheric exposure results. For ZL114A aluminum alloy, 10-year atmospheric monitoring data from a tropical marine environment were processed to compile climatic and chemical environment spectra. A laboratory accelerated corrosion environment spectrum was prepared via weighted concentration of environmental factors. Atmospheric corrosion monitoring (ACM) and electrochemical workstation measurements determined corrosion current and conversion coefficients under varying temperature, humidity, and acid solution conditions. The cumulative corrosion electricity for 10-year island atmospheric exposure was 3,050,339.15 C. Laboratory weight loss tests yielded the average corrosion weight loss rate per unit area. The equivalent acceleration relationship for ZL114A alloy under the compiled spectrum was 74 h/a. Verification via SEM, CT scanning, and fatigue testing compared surface damage morphology, pit dimensions, fatigue life, and fracture morphology of specimens exposed to atmospheric conditions for 6 months, 1 year, and laboratory accelerated corrosion for 72 h. Results confirm identical corrosion damage modes and severity consistent with the derived equivalent acceleration relationship. The 72 h accelerated specimens exhibited damage between 6-month and 1-year atmospheric exposures, closer to 1-year exposure, validating the method's feasibility.